Surrounded by middle-aged white guys — a sepia snapshot of the days when such pols ran Washington like their own men’s club — Joe Wilson yelled “You lie!” at a president who didn’t.

But, fair or not, what I heard was an unspoken word in the air: You lie, boy!

The outburst was unexpected from a milquetoast Republican backbencher from South Carolina who had attracted little media attention. Now it has made him an overnight right-wing hero, inspiring “You lie!” bumper stickers and T-shirts.

The congressman, we learned, belonged to the Sons of Confederate Veterans, led a 2000 campaign to keep the Confederate flag waving above South Carolina’s state Capitol and denounced as a “smear” the true claim of a black woman that she was the daughter of Strom Thurmond, the ’48 segregationist candidate for president. Wilson clearly did not like being lectured and even rebuked by the brainy black president presiding over the majestic chamber.

I’ve been loath to admit that the shrieking lunacy of the summer — the frantic efforts to paint our first black president as the Other, a foreigner, socialist, fascist, Marxist, racist, Commie, Nazi; a cad who would snuff old people; a snake who would indoctrinate kids — had much to do with race.

I tended to agree with some Obama advisers that Democratic presidents typically have provoked a frothing response from paranoids — from Father Coughlin against F.D.R. to Joe McCarthy against Truman to the John Birchers against J.F.K. and the vast right-wing conspiracy against Bill Clinton.

But Wilson’s shocking disrespect for the office of the president — no Democrat ever shouted “liar” at W. when he was hawking a fake case for war in Iraq — convinced me: Some people just can’t believe a black man is president and will never accept it.

“A lot of these outbursts have to do with delegitimizing him as a president,” said Congressman Jim Clyburn, a senior member of the South Carolina delegation. Clyburn, the man who called out Bill Clinton on his racially tinged attacks on Obama in the primary, pushed Pelosi to pursue a formal resolution chastising Wilson.

“In South Carolina politics, I learned that the olive branch works very seldom,” he said. “You have to come at these things from a position of strength. My father used to say, ‘Son, always remember that silence gives consent.’ ”

Barry Obama of the post-’60s Hawaiian ’hood did not live through the major racial struggles in American history. Maybe he had a problem relating to his white basketball coach or catching a cab in New York, but he never got beaten up for being black.

Now he’s at the center of a period of racial turbulence sparked by his ascension. Even if he and the coterie of white male advisers around him don’t choose to openly acknowledge it, this president is the ultimate civil rights figure — a black man whose legitimacy is constantly challenged by a loco fringe.

For two centuries, the South has feared a takeover by blacks or the feds. In Obama, they have both.

The state that fired the first shot of the Civil War has now given us this: Senator Jim DeMint exhorted conservatives to “break” the president by upending his health care plan. Rusty DePass, a G.O.P. activist, said that a gorilla that escaped from a zoo was “just one of Michelle’s ancestors.” Lovelorn Mark Sanford tried to refuse the president’s stimulus money. And now Joe Wilson.

“A good many people in South Carolina really reject the notion that we’re part of the union,” said Don Fowler, the former Democratic Party chief who teaches politics at the University of South Carolina. He observed that when slavery was destroyed by outside forces and segregation was undone by civil rights leaders and Congress, it bred xenophobia.

“We have a lot of people who really think that the world’s against us,” Fowler said, “so when things don’t happen the way we like them to, we blame outsiders.” He said a state legislator not long ago tried to pass a bill to nullify any federal legislation with which South Carolinians didn’t agree. Shades of John C. Calhoun!

It may be President Obama’s very air of elegance and erudition that raises hackles in some. “My father used to say to me, ‘Boy, don’t get above your raising,’ ” Fowler said. “Some people are prejudiced anyway, and then they look at his education and mannerisms and get more angry at him.”

Clyburn had a warning for Obama advisers who want to forgive Wilson, ignore the ignorant outbursts and move on: “They’re going to have to develop ways in this White House to deal with things and not let them fester out there. Otherwise, they’ll see numbers moving in the wrong direction.”